Date: I think it was made between 1970 and 2000.
The computer appears as a panel on a wall with blinking lights. Green ooze is seeping from it, it has been spliced with living tissue (?), which is what caused it to evolve and become sentient and see humans as a threat to it’s existence.
It killed people with the elevator (but it’s not about a killer elevator) and it could suck out the “energy” from people through telephones.
In one scene someone picked up the receiver of a telephone and he disappeared completely probably via some cheap animation effect. The “brain” of the computer consumed him as a form of energy to sustain itself.
In another scene, the bulletproof glass main doors of the building were closing and the people threw a chair between them but it disappeared.
They lived in constant fear, not knowing what can they touch without getting killed.
Demon Seed (1977)
Cross talk (1982)
The Lift (1983)
The Tower (1985)
The Tower (1993)
The Outer Limits – The Haven (1999)
The Shaft AKA Down (2001)
Resident Evil (2002)
666 Park Avenue (TV Series 2012-2013)
It’s an almost 7 year old question on another site.